Time to exhaustion at estimated functional threshold power in road cyclists of different performance levels

This study assessed the functional threshold power and the time to exhaustion estimated from the Allen & Coggan test and verify whether performance level has an influence on this parameter

Effects of a low-carbohydrate diet on body composition and performance in road cycling: A randomized, controlled trial

Low-carbohydrate diets are frequently used to improve performance in endurance sports, often with contradictory results. This study aimed to assess whether a low-carbohydrate diet can outperform an isocaloric conventional diet for improving body composition and performance in a sample of twenty-six trained male road cyclists (previous experience in cyclosportive events, 7.6 ± 4.4 years; age, 26.9 ± 4.9 years; weekly training volume, 7.8 ± 2.9 hours; height, 176 ± 7 centimeters; body fat percentage, 9.7 ± 0.8 %; weight, 65.3 ± 2.3 kg). Detraining and pre-treatment periods in which nutrition and training were standardized were followed by an eight-week long intervention in which cyclists consumed either a low-carbohydrate diet (15 % of calories from carbohydrates) or a conventional endurance sports diet while maintaining the same training volumes and intensities. Body composition was assessed through electrical impedance, and performance was evaluated through a twenty-minute time trial performed on a smart bike trainer. The results revealed an overall improvement over time in absolute and relative power, body mass, and body fat for both groups, whilst the improvement in absolute power was comparable. The improvements seen in relative power (p = 0.042), body mass (p = 0.006), and body fat (p = 0.01) were significantly higher in the low-carbohydrate group. We concluded that eight weeks of a low-carbohydrate diet significantly reduced body weight and body fat percentage, and improved 20-minute relative power values in a sample of road cyclists when compared to an isocaloric conventional diet. Las dietas bajas en carbohidratos se usan con frecuencia para mejorar el rendimiento en los deportes de resistencia, a menudo con resultados contradictorios. Este estudio tuvo como objetivo evaluar si una dieta baja en carbohidratos puede superar a una dieta convencional isocalórica para mejorar la composición corporal y el rendimiento en una muestra de veintiséis ciclistas de carretera masculinos entrenados (experiencia previa en eventos cicloportivos, 7, 6 ± 4, 4 años; edad, 26, 9 ± 4, 9 años; volumen de entrenamiento semanal, 7, 8 ± 2, 9 horas; altura, 176 ± 7 centímetros; porcentaje de grasa corporal, 9, 7 ± 0, 8 %; peso, 65, 3 ± 2, 3 kg). Los períodos de desentrenamiento y pretratamiento, en los que se estandarizaron la nutrición y el entrenamiento, fueron seguidos por una intervención de ocho semanas de duración en la que los ciclistas consumieron una dieta de bajo contenido en carbohidratos (15 % de calorías de los carbohidratos) o una dieta convencional para deportes de resistencia, manteniendo los mismos volúmenes de entrenamiento e intensidades. La composición corporal se evaluó a través de la impedancia eléctrica y el rendimiento se evaluó a través de una prueba contrarreloj de veinte minutos realizada en un rodillo de bicicleta inteligente. Los resultados revelaron una mejora general en el tiempo en cuanto a potencia absoluta y relativa, masa corporal y grasa corporal para ambos grupos, mientras que la mejora en potencia absoluta fue comparable. Las mejoras de la potencia relativa (p = 0, 042), la masa corporal (p = 0, 006) y la grasa corporal (p = 0, 01) fueron significativamente mayores en el grupo bajo en carbohidratos. Se concluye que ocho semanas de una dieta baja en carbohidratos redujeron significativamente el peso corporal y el porcentaje de grasa corporal, y mejoraron los valores de potencia relativa de 20 minutos en una muestra de ciclistas de carretera en comparación con una dieta convencional isocalórica

Influence of turbulence on the dynamo threshold

We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with given amplitude, injection scale and correlation time. The addition of a stochastic noise to the mean velocity significantly alters the dynamo threshold. When the noise is at small (resp. large) scale, the dynamo threshold is decreased (resp. increased). For a large scale noise, a finite correlation time reinforces this effect

Kinematics and morphology of ionized gas in Hickson Compact Group 18

We present new observations of $H\alpha$ emission in the Hickson Compact Group 18 (HCG 18) obtained with a scanning Fabry-Perot interferometer. The velocity field does not show motions of individual group members but, instead, a complex common velocity field for the whole group. The gas distribution is very asymmetric with clumps of maximum intensity coinciding with the optically brightest knots. Comparing $H\alpha$ and HI data we conclude that HCG 18 is not a compact group but instead a large irregular galaxy with several clumps of star formation.Comment: Accepted for publication in Astronomical Journal (13p 6 figures

Training needs and development of online AT training for healthcare professionals in UK and France

Background: Assistive Technologies (AT) in healthcare can increase independence and quality of life for users. Concurrently, new AT devices offer opportunities for individualised care solutions. Nonetheless, AT remains under-utilised and is poorly integrated in practice by healthcare professionals (HCPs). Although occupational therapists (OTs), physiotherapists and speech and language therapists (SLTs) consider that AT solutions can offer problem-solving approaches to personalised care, they have a lesser understanding of application of AT in their practice. In this paper, we report findings of a survey on AT knowledge and experiences of HCPs in UK and France. Training needs also explored in the survey are presented in a separate paper on development of online training for the ADAPT project. Method: A survey of 37 closed/open questions was developed in English and French by a team of healthcare researchers. Content was informed by published surveys and studies. Email invitations were circulated to contacts in Health Trusts in UK and France ADAPT regions and the survey was hosted on an online platform. Knowledge questions addressed AT understanding and views of impact on user’s lives. Experience questions focussed on current practices, prescription, follow-up, abandonment and practice standards. 429 HCPs completed the survey (UK=167; FR=262) between June and November 2018. Key results: Participants were mainly female (UK 89.2%; FR 82.8%) and qualified 10+ years (UK 66.5%; FR 62.2%). A key group in both countries were OTs (UK 34.1%; FR 46.6%), with more physiotherapists and SLTs in UK (16.8%, 16.8%; Vs. FR 6.5%, 2.3%), and more nurses in France (22.1% Vs. UK 10.8%). More HCPs were qualified to degree level in France (75.2%; UK 48.5%, p<0.001). In terms of knowledge, all HCPs agreed that AT helps people complete otherwise difficult or impossible tasks (UK 86.2%; FR 94.3%) and that successful AT adoption always depends on support from carers, family and professionals (UK 52.7%; FR 66.2%). There were some notable differences between countries that require further exploration. For example, more French HCPs thought that AT is provided by trial and error (84.7%, UK 45.5%, p<0.001), while more UK HCPs believed that AT promotes autonomous living (93.4%; FR 42.8%, p<0.001). Also, more French HCPs considered that AT refers exclusively to technologically-advanced electronic devices (71.8%, UK 28.8%, p<0.001). In both countries, top AT prescribers were OTs, physiotherapists and SLTs. Respondents had little/no knowledge in comparing/choosing AT (UK 86.8%; FR 76.7%) and stated they would benefit from interdisciplinary clinical standards (UK 80.8%; FR 77.1%). A third of HCPs did not know if AT users had access to adequate resources/support (UK 34.1%; FR 27.5%) and rated themselves as capable to monitor continued effective use of AT (UK 38.9%; FR 34.8%). Conclusion: Knowledge and application of AT was varied between the two countries due to differences in health care provision and support mechanisms. Survey findings suggest that HCPs recognised the value of AT for users’ improved care, but had low confidence in their ability to choose appropriate AT solutions and monitor continued use, and would welcome AT interdisciplinary clinical standards

Characteristics of pedaling muscle stiffness among cyclists of different performance levels

Background and Objectives: The aim of the present study was to compare the impact of an incremental exercise test on muscle stiffness in the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gastrocnemius (GL) among road cyclists of three performance levels. Materials and Methods: The study group consisted of 35 cyclists grouped according to their performance level; elite (n = 10; professional license), sub-elite (n = 12; amateur license), and recreational (n = 13; cyclosportive license). Passive muscle stiffness was assessed using myometry before and after an incremental exercise test. Results: There was a significant correlation between time and category in the vastus lateralis with stiffness increases in the sub-elite (p = 0.001, Cohen’s d = 0.88) and elite groups (p = 0.003, Cohen’s d = 0.72), but not in the recreational group (p = 0.085). Stiffness increased over time in the knee extensors (RF, p < 0.001; VL, p < 0.001), but no changes were observed in the knee flexors (GL, p = 0.63, BF, p = 0.052). There were no baseline differences among the categories in any muscle. Conclusions: Although the performance level affected VL stiffness after an incremental exercise test, no differences in passive stiffness were observed among the main muscles implicated in pedaling in a resting state. Future research should assess whether this marker could be used to differentiate cyclists of varying fitness levels and its potential applicability for the monitoring of training load. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Effect of Copper Doping on Charge Ordering in La 1/3 Ca 2/3 Mn 1 - y Cu y O 3 (0 ≤ y ≤ 0.07)

Electron microscope studies have shown that the presence of copper suppresses the formation of a regular superstructure, which is characteristic of the undoped starting compound, beginning already from low concentrations (y=0.01). Differential scanning calorimetry revealed a substantial decrease in the transition entropy at the onset of charge ordering in copper-doped samples as compared to the starting compound. Doping with copper destroys long-range charge-orbital ordering and retains apparently only short-range orderyesBelgorod State Universit